One of the most lavish weddings of recent years has been taking place in the Brazilian city of Sao Paulo.
The couple are keen horse riders
Greek billionairess Athina Roussel Onassis, 20, has exchanged vows with Brazil's Olympic horse-rider Alvaro Alfonso de Miranda, 32.
Tight security was in place for the ceremony in the immaculate gardens of an art museum in the city.
Ms Onassis, whose fortune is estimated at about $2.7bn, met her future husband at a riding academy in Belgium in 2002.
She is a granddaughter and sole heiress of the late Greek shipping tycoon, Aristotle Onassis.
Many of the 700 guests were delayed at the entrance at the start of the ceremony planned for 2130 GMT because of heavy security.
Each guest had to go through metal detectors
Each guest had been issued with a photo ID card, complete with a bar code.
There were also checks with metal detectors and all cameras were confiscated.
However, one French photographer did manage to get in dressed as a waiter. When discovered, his camera was confiscated but he did reportedly manage to smuggle out a digital memory card, containing what may prove to be the only publicly-available photographs of the event.
Organisers have refused to proved details about the wedding, claiming they were sworn to secrecy.
But rumours about the extravagance of the wedding have abounded in the Brazilian media, the BBC's Steve Kingstone in Sao Paulo says.
It is said that 1,000 bottles of champagne were ordered and Italian marble flooring was temporarily laid down where the ceremony was due to take place, our correspondent says.
Guests were asked not to bring gifts, but to make cash donations to a local orphanage instead.
The Onassis dynasty is one of the country's most famous families.
It is also of particular interest because - although fabulously wealthy - the family is being plagued by controversy and tragic deaths.
In the latest twist of fate, Ms Onassis looks set to have a bruising battle in court for control of the Onassis charitable foundation, which is also believed to have around $1bn at its disposal.
It had been expected that when she turns 21 in the new year, she would automatically become president of the foundation and thus in charge of dispensing millions of dollars to good causes around the world, the BBC's Richard Galpin in Greece reports.
But the directors in Athens - none of whom are relatives - are alleged to have changed the rules, our correspondent says.
The new regulations stop her becoming president because she does not speak Greek and did not go to university.